| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] once [prep] a | 19 |
|
| 2 | [pers pn] once [prep] a | 16 |
|
| 3 | [pron] once in a | 10 |
|
| 4 | it once [prep] a | 6 |
|
| 5 | it once [prep] a | 6 |
|
